1. Field of the Invention
The present invention relates to a power supply, and more particularly to an over current protection circuit for power supplies.
2. Description of the Prior Art
In the current art, electronic power source products, such as a power supply, mounts an over current protection circuit (O.C.P) to avoid breakages caused by users or malfunctioning products.
In order to protect an overloaded circuit, a switching power supply is used. The switching power supply limits its output current to a certain range. However, the switching power supply wastes energy and causes high temperatures when the circuit is over current for long periods.
Hence, in order to improve upon such problems, over current protection circuits operate in two ways. The first is a latch off mode, and the second is an auto recover mode. In latch off mode, the switching power supply automatically disables its output when the output end of the switching power supply shorts or is over current. It then cold-boots to try to supply power again when the output end of the switching power supply has returned to normal levels.
In auto recover mode, the over current protection circuits further operate in two detailed ways. The first is a cycle-by-cycle mode, and the second is a hiccup mode. In cycle-by-cycle mode, the switching power supply may waste energy in each operation cycle. In hiccup mode, the switching power supply automatically disables its output when the output end of the switching power supply shorts or overloads, and then automatically warm-boots to try to supply power again. The switching power supply in hiccup mode may repeatedly disable its output and automatically warm-boots until the output end of the switching power supply has returned to normal.
Hence, in order to design such previous electronic power source products such as a switching power supply, that can operate in latch off mode and auto recover mode simultaneously, users further mount more expensive controllers or combine extras with various mode circuits in electronic power source products. However, such improved products are expensive and have complex circuits.